THURSDAY, May 6 (HealthDay News) -- Chronic pain, which often occurs without an apparent cause, may be the result of accidental reprogramming of more than 2,000 genes in the peripheral nervous system, new research suggests.

The finding may someday lead to new drugs that treat pain by correcting the activity of specific genes, a method called transcription therapy, the researchers said.

In the study, published online in the journal Genome Research, Mayo Clinic researchers focused on dorsal root ganglion neurons of the peripheral nervous system in rodents. These nerve cells are suspected to be involved in pain.

The researchers studied hundreds of millions of messenger RNA (mRNA) molecules -- the messengers of gene activity. The team identified more than 10,000 new exons (sections of the genome involved in creating proteins) and about 400 candidate genes implicated in the pain response.

The new approach "may be an efficient new approach to a wide array of problems in neuroscience research," Dr. Andreas Beutler, Mayo Clinic oncologist and corresponding author on the study, added in a news release.

Chronic pain, which affects 50 million Americans, often fails to respond to available treatments, and costs the United States about $100 billion in health costs, lost time at work and other economic effects annually, according to the U.S. National Institutes of Health.